Grinding machine for reamers and like tools



Nov. 2, 1937. A. c. HOEH GRINDING MACHINE FOR REAMERS AND LIKE TOOLS Filed Oct. 26, 195i 2 Sheets-Sheet 1 ATTO RN EY Nov. 2, 1937.

AC. HOEH GRINDING MACHINE FOR REAMER'S AND LIKE TOOLS 2 Sheets-Sheet 2 Filed 001:. 26, 1951 ATTORNEYS Patented Nov. 2, 1937 Unit STATES attest PATET Fri 1;-

GRINDING MACHINE FOR REAMERS AND LIKE TOOLS 6 Claims.

The present invention pertains to a novel grinding machine of a type particularly adapted for grinding the cutting blades on such tools as reamers and similar boring or milling tools in a manner to definitely determine and provide the clearance angle that is required on the blades of the particular tool which it is handling in order to produce a smoother surface by the tool when it is put in use and in order to increase the useful life thereof between grindings.

The primary object of the present invention is to provide a grinding machine including a grinding wheel that may be adjusted to give the required clearance angle on the cutting blades of various tools by adjusting the wheel relative to a vertical plane whereby its grinding face contacts with the cutting blades that are held in a horizontal plane whereby the proper clearance angles are ground on the cutting blades without relative to a horizontal plane as is the. common practice. The clearance angles on such tools as reamers in order to facilitate efiicient operation and to prevent scoring of the bore when the tool is being withdrawn therefrom, must ordinarily vary throughout the entire length of the cutter blade. To attain a variable clearance angle throughout the entire length of the blade the present machine pivotally supports the grinding 3 wheel and its motor and provides an arm on the pivotal support that controls the pivotal movement of the motor and grinding wheel as well as indexing means that shows the operator the exact angle being ground. The arm engages a cam that is mounted in fixed relation to the work to move to and fro therewith and as the arm raises and lowers as a result of its contact with said cam the motor and grinding wheel are moved pivotally and in this manner the angle at which the Work is governed by the cam. The cam which is engaged by said controlling arm is provided with a definite form that results in the required clearance angle at various positions on the cutting blade and the indexing means makes it possible'to adjust the wheel to the required angle that is varied by said cam,

Another object of the present invention is to provide a grinding machine wherein the grinding wheel and its driving motor are mounted upon a rotatable head that is controlled by an arm which is integral therewith and which engages a cam in a manner whereby movement of said cam causes partial rotation of the grinding wheel supporting member and causes the angle the necessity of adjusting the blades at an angle the grinding surface of the wheel contacts with at which said grinding wheel engages the work to Vary. Mounted upon themotor supporting head is a finger that co-acts with graduations on a stationary supporting member which makes it possible for the operator to determine the ex- 5 act amount of clearance angle being ground upon the work at any stage in the grinding operation.

With the above and other ends in view the invention consists in matters hereinafter set forth and more particularly pointed out in the ap- 10 pended claims, reference being had to the accompan-ying drawings in which Figure 1 is a side elevation of the present grinding machine, and

Fig. 2 is a top plan View of the machine, the 5 motor being removed and the work supporting members being illustrated in broken lines.

Like characters of reference are employed throughout to designate corresponding parts.

It is understood that mechanical details vary 20 in grinding machines of difierent types but all cylindrical grinding machines operate on the same general principle which is common and well known. This invention provides a mechanism that adapts itself to the principle of oper- 25 ation found in conventional cylindrical grinding machines and therefore may be employed to convert such machines to the present use in grinding the cutting blades on reamers and boring tools. The various sliding movements and ad- 30 justments of the work supporting table are common and well known in such machines as are the parts and their functions in attaining the adjustments and movements and inasmuch as such parts form no part of the present invention they 35 are illustrated and described in a general manner.

The present machine, in the manner of conventional grinding machines, includes a base i and a horizontally extending bed 2 provided with ways 3. The usual work supporting table 4 is 40 pivotally mounted by means of a pin 4' upon a plate 5 that has a tongue 6 which slides in the ways 7 in a plate 8, the plate 8 being slidably mounted upon the ways 3.

The above described mounting of the work sup- 5 porting table 4 permits the same to be moved laterally and longitudinally as Well as pivotally. The use of worms, screws and racks and pinions are contemplated for attaining the desired movements and inasmuch as the same are old and 5 well known they are omitted from the drawings and description in order that the part that forms the invention may be more readily understood.

A head stock 9 and a tail stock It are secured by means of bolts and nuts H to the table 4, the 55 latter being provided with grooves E2 to receive the heads of the bolts. Between the head and foot stocks is mounted a reamer body it having a plurality of cutting blades i l that are to be groundwith a clearance angle that permits efficient reaming operations and permits the tool being retracted from a bore without scoring the same.

On top of the base i is rigidly secured a bracket it that has a vertically disposed portion it that is rounded as at i! to correspond to a true semicircle. A boss 58 is formed on the vertical portion iii of the bracket to project outwardly, the boss being bored to receive a trunnion shaft is having a head 20 formed on the inner end thereof. The outer end of the trunnion shaft l9 projects outwardly a short distance beyond the end of the boss it as at El and is then reduced in diameter as at 22 and screw threaded as at 23. An arm 24 is'rotatably mounted upon the reduced portion 22 of the shaft and is jammed against the end of the enlarged portion of the shaft by a nut 25 having a projecting arm 26 to facilitate hand operation thereof. When the arm 24 is jammed by the nut 25 against the end of the shaft i9 it becomes secured to said shaft in a manner whereby raising or lowering of said arm rotates said shaft and the head 25. A weight 2 3' is mounted on the outer end of the arm 26.

Secured upon the head 20 is a bracket 2'? that supports a bearing member 28 in which is rotatably mounted a shaft 29 having a grinding wheel 38 secured on the end thereof. The bracket 2'! also supports an electrically driven motor 3! that has its drive shaft 32 connected by a belt 33 to the shaft 29 to drive the same. In this manner the shaft 29, grinding wheel 30 and the motor 3| are mounted to rotate with the shaft l9.

Mounted upon the work supporting table A is a supporting member 34 that supports a cam 35 and the arm Bi l is provided with a roller 36 that ordinarily rests upon the cam. As the cam moves the arm 2 is caused to raise or lower as a result of the contact of the roller 36 with the cam.

The head 28 carries a pointer 31 that co-acts with a series of graduations on the semi-circular portion ll of the bracket l5.

The bracket 15 is provided with clamping members 38 in which is clamped a shaft 39' that has a clamping head in which is mounted an outwardly extending shaft 46 that carries a vertically extending finger M which is adjustable in height. The adjustable finger M is set at a height that is determined by a gauge that is provided with all such machines so that when one of the reamer blades 14 rests thereon as illustrated in Fig. 1 the side walls thereof are in a true horizontal plane.

In operating the present machine for thepurpose of obtaining more than one clearance angle the nut 25 is loosened. The head 20, motor and grinding wheel are then rotated on the trunnion shaft is until the pointer 31 points to the degree of clearance required on the graduations 38 at which time the roller 36 on the arm 24 is brought into contact with the highest point on the cam 35. The trunnion shaft is then held in the position andthe nut 25 is tightened so that the arm 24 holds the face of the grinding wheel tipped at an angle corresponding to the angle of clearance desired on the cutting blades M. The work table is then moved longitudinally and carries the reamer body and cam in a manner whereby the cutting blade is ground with a variable clearance angle that is controlled by movement of the arm 24 as the height of the cam at the contact point therewith changes, the weight 24 serving to maintain the arm in contact with the cam.

When it is desired to grind the same clearance angle throughout the entire length of the blade it is necessary to hold the grinding Wheel in the required plane permanently. This is accomplished by securing the trunnion shaft l9 against movement. To hold the trunnion shaft stationary there is provided a counterbore 42 formed in what is ordinarily the outer face of the arm 2 5. When the nut 25 is removed the arm 24 may be turned so that the side having the counterbore 42 becomes adjacent the boss I8 and when in such a position the portion of the trunnion shaft i9 thatprojects beyond the end of the boss I8 projects into the counterbore 32. The nut 25 is then screwed onto the portion 23 in a manner to force the face of the arm against the outer end of the boss l8 and thus hold the trunnion shaft and grinding wheel in a fixed position.

From the above description in connection with the drawings, it will be apparent that the assembly, whether operated to produce the cutting face with the helical clearance or with uniform clearance, has its grinding action such as to concurrently produce the contour of the cutting edge as well as the clearance desired, doing this with accuracy and relative rapidity. This result is ob-' tained by reason of the particular mounting of the grinding wheel.

As will be seen and understood, the grinding face of the grinding wheelthe latter being of the cup-shape typetravels in a path which corresponds to a plane that extends normal or perpendicular to the axis of rotation of the wheel. With the axis of the wheel extending to and inter secting the axis of the trunnion 24-the latter extending horizontally and being constant in direction, it can be seen that this plane of the grinding face is shiftable bodily about such trunnion axis. And since the latter is remote from the plane, it can be understood that the plane itself is shiftable through a vertical arc.

However, this ability to shift such plane through the vertical are sets up a number of conditions. For instance, the horizontal diameter of the grinding face extends parallel to the axis of trunnion 24, and being a constant distance therefrom Will swing in an are about the axis as the center of swinging movement; and each point of the vertical diameter of the grinding face will have a similar'relation to the axis of the trunnion. But since the grinding face is itself similar to a plane-and therefore tangent to the arc traversed by the horizontal diameter of the face there is set up the conditions of a variation in the length of the radius of swinging movement as between points on such vertical diameter of the grinding face. The shortest radius will be at the position of the horizontal diameter, the radius increasing progressively away from such horizontal diameter along the vertical diameter.

Hence, when the plane of the grinding face is shifted about the axis of the trunnion relative to a fixed point-the positioned blade face, for in the swinging movement of the grinding wheel, controllably I provided by the cam, will not only provide the conditions of a variable clearance condition, but will, at the same time, control the contour of the cutting edge of the blade. "This condition is present whether the cutting edge contour be of uniform radii relative to the axis of :the' reamer, considered in the direction of length of the cutting edge, 'or be of varied radii. In the former, the clearance angle will be constant, sincethe radius of the cutting edge is constant, while in the varied radii form the clearance angle varies in accordance with the varied radii, and producing the helical clearance angle effect. In other words, the clearance angle is made complemental to thecontour of the cutting edge of the blade,- whether the contour be of constant radius or of varied radii.

:And this condition will be present regardless of the clearance angle selected. For instance, if the pointer 3Tbe set'at the zero mark when the roller 36 is at the high point of the cam and with the active zone of the grinding face at the point which forms the outer diameter of the tool, the advance of the work in the direction of the tool axis provides the control activity of the cam and will set up the cutting edge contour and the complemental helical clearance, with the clearance degree initially based on the setting of the pointer. If the pointer has been set at a different point on the scale, the clearance angle will be varied from that previously present. This permits ready duplication, since it is necessary to know only the initial position of the pointer to enable the duplicates to be similarly formed by locating the pointer at the same place. With the pattern cam active, the pointer will move over its scale as the operation proceeds, thus permitting the operator to note the clearance angle at all times.

If, instead of using thecam and thus setting up the above conditions, the alternative operation in which the trunnion is held against rotation after having been set, the plane of the grinding face remains constant in position, the result being 7 that the cutting edge contour will be parallel with the opposite edge of the blade and the clearance will remain uniform as to degree of angularity. But in each instance, both'the contour of the cutting edge and the clearance therefor will be produced concurrently with the clearance complemental to the contour;

During either type of operation the direction of advance of the tool is parallel with the axis of the trunnion, thus corresponding tothe direction of the horizontal diameter of the wheel or parallel to such diameter when viewed in a horizontal plane. Through the ability to adjust the work support pivotally at 4' the axis of the tool and the horizontal diameter of the grinding face may be parallel or varied from parallelism, when viewed in vertical plane, but the direction of advance of the tool presents the constant parallelism referred to.

Although a specific embodiment of the present invention has been illustrated and described it is to be understood that various changes may be made within the scope of the appended claims without departing from the spirit of the invention and such changes are contemplated.

What I claim is: V

1. In a machine for grinding the cutting faces of cutting tools of the reamer type, wherein the cutting face is formed with a cutting edge and its clearance face, a driven grinding wheel of the cup-shaped type and mounted to cause its grinding face to be'opera'tive on a plane extending normal to the wheel axis, a work support adaptedlto present the work to the grinding face with the length dimension of the face to be ground extending substantially-in correspondence with or parallel to a diameter'of the wheel grinding face", with the support movable in the direction of length of the work face,-and means for supporting the grinding wheel to swing about an axis extending parallel to and positioned remote from said grinding face I diameter to permit swinging of the grinding face in a direction normal to such diameter, whereby the grinding face will traverse the work face transversely of the length of such work face to'concurrently grind a zone of the contour and its clearance face with the clearance face complemental to the edge contour, the clearance angle of the zone being dependent upon the position of the wheel within its range of swinging movement,said wheel supporting means includingcontrol mechanism operative to cause controlled swinging movement of the wheel Within the range of its swinging movement, whereby" the edge contour and the clearance angle'will be'varied' relative to the tool axis in the direction of length of the face with the variation in the direction of the tool radius.

2. In a machine for grinding the cutting faces of cutting tools of the reamer type, wherein the cutting face is formed with a cutting edge and its clearance face, a driven grinding wheel of the cup-shaped type and mounted to cause its grinding face to be operative on a plane extending normal to the wheel axis, a work support adapted to present the work to the grinding face with,

the length dimension of the face to be ground extending substantially in correspondence with or parallel to a diameter of the wheel grinding face with the support movable in the direction of length of the work face, and means for supporting the grinding wheel to swing about an axis extending parallel to and positioned remote from said grinding face diameter to permit swinging of the grinding face in a direction normal to such diameter, whereby the grinding face will traverse the work face transversely of the length of such work face to concurrently grind a zone of the contour and its clearance face with the clearance face complemental to the edge contour, the clearance angle of the zone being dependent upon the position of the wheel within its range of swinging movement, said wheel supporting means including control mechanism operative at will to cause controlled swinging movement of the wheel within its range of swinging movement or to retain the wheel at a definite point within such range of swinging movement, whereby cutting faces differing as to characteristics may be ground.

3. In a machine for grinding the cutting faces of cutting tools of the reamer type, wherein the cutting face is formed with a cutting edge and its clearance face, a driven grinding wheel of the cup-shaped type and mounted to cause its grinding face to be operative in a plane extending normal to the wheel axis, a work support adapted to present the Work to the grinding face with the length dimension of the face to be ground extending substantially in correspondence with or parallel to a diameter of the wheel grinding face with the support movable in the direction of length of the work face, means for supporting the grinding wheel to swing about an axis extending parallel to and positioned remote from said grinding face diameter to permit swinging of said wheel face, said means including a trunnion the axis of which forms the axis of such swinging movement of the wheel, said trunnion being rotative on its axis and being positioned to cause the swinging movement: to be in a direction normal to said wheel diameter, and means operative to control the position of said trunnion within its range of rotative movement, whereby the grinding face will traverse the work face transversely of the length of said work face to concurrently grind a zone of the contour and its clearance face with the clearance face complemental to the edge contour, the clearance angle of the zone being dependent upon the position of the trunnion within the range of its pivotal movement, said control means for the trunnion being operative at will to cause controlled free movement of the trunnion within its range of pivotal movement, whereby the edge contour and the clearance angle will be con- 'trollably varied relative to the tool axis in the direction of length of the work face with the variation in the direction of tool radius.

4. A machine as in claim 3 characterized by said control means being operative at will to retain the tru'nn'ion in'a definite adjusted posi-' tion within the range of such pivotal movement, whereby cutting faces differing in characteristic may be ground.

i 5;A machine as in claim 3 characterized in that the control means includes an arm projecting laterally'of I the trunnion, and a cam formation'movablewith the work-support and co-operative with the arm to control the pivotal movements of the trunnion during advance of the work in the direction of the work axis.

6. A machine as in claim.3 characterized in that the control means includes an arm projecting laterally of the trunnion, and a cam formation movable with the work-support and co-operative with the arm to control the pivotal movements of the trunnion during advance of the work in the direction of the work axis, the connections between arm and'trunnion being such-as to permitthe' arm' to be rendered inactive in the trunnion control and securing of the trunnion in definite position within its range of pivotal movement.

ALBERT C. I-IOEH. 

